<!DOCTYPE html><!--h5-->
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>系统登录</title>
    <style>

        .login-box {

            border:  1px  solid;
            border-radius: 20px;
            margin-left: 300px;
            margin-top: 400px;

        }

    </style>
</head>
<body>
<div class="login-box" >
    <div>
        <label>用户名:</label> <input/>
    </div>
    <div>
        <button id="btnLogin">登录</button>
    </div>

</div>

</body>
<script>

    document.getElementById('btnLogin').onclick = function () {
        window.location.href = "index.html";
    }



</script>
</html>